Pop-kun (ポップ君 Poppu-kun?) is the official term for small, colorful notes, playing their role as main icons in the Pop'n Music series.
Original[]
White
Yellow
Green
Red
Blue
Pop'n Stage[]
White
Yellow
Green
Red
Blue
Utacchi[]
Red
Blue
Yellow
Green
Pop'n Music Da!![]
White (A, P, Q, Z)
Pink (L, O, S, W, X)
Yellow (C, D, E, I, K)
Green (B, F, G, R, T, V)
Blue (H, J, M, N, U, Y)
Red (Space Bar)